The Bronx, in terms of rapid transit service, is traditionally seen as IRT territory. The IND only built a single line (with just 3 tracks) in the Bronx, under Grand Concourse—a line which is parallel with the IRT Jerome Av line and is just 2-4 blocks east of it. This line is now serviced by the B and D trains, with D trains running all times to 205th St, and B trains running on peak to Bedford Park Blvd—the second to last stop. Off peak, B trains terminate at 145th St, and the B doesn’t run during late nights or weekends. This makes the Concourse line a rather lonely one. While the IND didn’t have huge plans for the Bronx, the Second System did provide for a significant extension of the Concourse line and construction of a line (with a couple branches) in the eastern Bronx, as the northern segment of the Second Avenue Subway (a lot more on this in the next installment of this series).

There is but one IND Second System provision that was constructed in the Bronx. The northern terminus of the Concourse line, at E 205th St in Norwood, has possibly the strangest track layout of any IND terminal station. It has tail tracks, but these are kept clear to be used as relay tracks (serving to turn trains around). There is no crossover between the northbound and southbound revenue tracks between Bedford Park Blvd and 205th St, so all revenue trains must pull into the station on what would be the northbound track, discharge passengers, move forward into the relay, and then reverse back onto the southbound track (trains may switch tracks when pulling into the relay, or when pulling out after reversing). Trains may also come into 205th St directly from the Concourse Yard on a middle track west of the station (railroad south), going directly into service at 205th St.

The reason for the odd track layout of this area is simple: 205th St was not intended to be the permanent terminus of the line. The Second System plans called for the line to be extended to Boston Road and Baychester Av, next to the present day site of Co-Op City. This extension would have improved the commute of many Bronx residents, eliminating much reliability on slow bus routes.